3,004 research outputs found

    Challenges in the industrialization process of low-volume production systems

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    A critical part of new product development projects is the industrialization process of new products which affects both time and the cost. The industrialization of new products or variants in low-volume production systems has some specific challenges which are caused by characteristics of low-volume products and production systems. Therefore, an exploratory case study is made within two Swedish manufacturing companies to understand these challenges and compare the industrialization process in high and low volume production systems. The results of the multiple case studies indicate four challenges including knowledge transfer from the projects into production, development of the work instructions, the need for a higher level of training of the operators and production system design and the obligatory tailoring of the new products to the existing production systems

    Bibliography of Supersonic Cruise Research (SCR) program from 1980 to 1983

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    A bibliography for the Supersonic Cruise Research (SCR) and Variable Cycle Engine (VCE) Programs is presented. An annotated bibliography for the last 123 formal reports and a listing of titles for 44 articles and presentations is included. The studies identifies technologies for producing efficient supersonic commercial jet transports for cruise Mach numbers from 2.0 to 2.7

    Weather Design Considerations for the TASAR Traffic Aware Planner

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    The Traffic Aware Planner (TAP) is a decision support automation tool for trajectory planning and optimization intended for use on todays flight deck. Drawing from a variety of on- and off-board data sources, TAP employs a sophisticated trajectory optimization algorithm that provides the aircrew with fuel- and time-saving reroute recommendations that are free of known conflicts with traffic, special use airspace, and severe convective weather. As this kind of weather is a significant part of the pilots decision-making process while planning trajectory changes en route, a series of investigations has been conducted into the integration of weather data and associated functionality into the TAP software. This paper reviews the weather data sources and functionality that have been incorporated into TAP to date, along with experience gathered in the course of the design process

    Exploring lean production in the flexible manufacturing systems environment: some tensions between features of advanced manufacturing technologies and new wave manufacturing strategies

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    Exploring lean production in the flexible manufacturing systems environment: some tensions between features of advanced manufacturing technologies and new wave manufacturing strategie

    NASA contributions to fluidic systems: A survey

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    A state-of-the art review of fluidic technology is presented. It is oriented towards systems applications rather than theory or design. It draws heavily upon work performed or sponsored by NASA in support of the space program and aeronautical research and development (R&D). Applications are emphasized in this survey because it is hoped that the examples described and the criteria presented for evaluating the suitability of fluidics to new applications will be of value to potential users of fluidic systems. This survey of the fluidics industry suggests some of the means whereby a company may use a fluidic system effectively either to manufacture a product or as part of the end product

    The ConWip Production Control System: a Literature Review

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    International audienceA growing body of literature dealing with ConWip has been observedduring the past decade. Considering the current industrial challengescharacterized by adaptability, product customization, shortened lead times andcustomer satisfaction, ConWip appears to be an effective and adaptedproduction control system for manufacturers. Given this context, this paper aimsto update the previous literature review about ConWip that was made in 2003and to provide an understanding key through an original classification method.This method allows the reader to distinguish papers that concentrate on ConWipsizing, ConWip performance, ConWip environment or on the comparison ofConWip with other PCS. It also provides a reading key about the researchapproach. Taking these criteria into account, this paper helps to answer thefollowing questions: how can ConWip be implemented? How can ConWip beoptimized? Why and when should ConWip be used? The paper then concludeswith some research avenues

    Aeronautical Engineering: A Continuing Bibliography with Indexes

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    This supplemental issue of Aeronautical Engineering: A Continuing Bibliography with Indexes lists reports, articles, and other documents recently announced in the NASA STI Database. The coverage includes documents on the engineering and theoretical aspects of design, construction, evaluation, testing, operation, and performance of aircraft (including aircraft engines) and associated components, equipment, and systems. It also includes research and development in aerodynamics, aeronautics, and ground support equipment for aeronautical vehicles. Each entry in the publication consists of a standard bibliographic citation accompanied, in most cases, by an abstract. The NASA CASI price code table, addresses of organizations, and document availability information are included before the abstract section. Two indexes-subject and author are included after the abstract section

    The effect of elevated water content on ethanol combustion

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    Ethanol is currently being considered as a potential alternative to traditional fuels. However, the fuel offers a low return in terms of energy output per dollar invested when compared to fossil fuels. More than 1/3 of the cost associated with bio-ethanol production is devoted to distillation and water removal. This study seeks to validate the use of hydrous ethanol as a practical fuel to be used in lieu of fossil fuels or anhydrous ethanol. Success would reduce the production cost associated with ethanol fuel. Hydrous ethanol was burned in a swirl-stabilized combustor, air is introduced at a constant flow rate through a dump diffuser, and fuels ranging from 0%-40% water by volume was tested for practicality. A stable flame was achieved with up to 35% water and the Lean Blow Out limit was determined for these fuels. Fuels ranging from 0% to 20% water were tested in greater detail. This included thermal mapping of the flame, exhaust temperature measurements, exhaust NOx, CO2, and O2 measurement, as well as CH* and OH* imaging of the low-flame region. Equivalence ratio was varied to include test points at 0.6, 0.8, 1.0 and 1.1. This range provides insight into flame behavior at extremely lean, lean, stoichiometric, and rich test conditions. Results revealed that exhaust heat rate, combustion efficiency, and combustor thermal efficiency were not affected negatively by elevated water content. However, flame temperature decreased as a result of water addition, particularly in the low flame region. CH*/OH* emissions in the low-flame region were also reduced due to the parasitic heat load of water vaporization and local quenching. The practical consequence of burning hydrous fuel was reduced exhaust temperature. This negative consequence, coupled with the desirable consequence of increased mass flow rate, did not appreciably affect the net exhaust heat rate. Reduced peak temperatures lead to exhaust NOx reductions. In conclusion, this study reveals that ethanol with proof as low as 140 behaves as a practical fuel and is recommended as a means of increasing the economic return when using ethanol as fuel in situations where increased volumetric consumption of the fuel is acceptable

    Aeronautical Engineering: A special bibliography with indexes, supplement 69

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    This bibliography lists 305 reports, articles, and other documents introduced into the NASA scientific and technical information system in March 1976

    Advanced Technology Spark-Ignition Aircraft Piston Engine Design Study

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    The advanced technology, spark ignition, aircraft piston engine design study was conducted to determine the improvements that could be made by taking advantage of technology that could reasonably be expected to be made available for an engine intended for production by January 1, 1990. Two engines were proposed to account for levels of technology considered to be moderate risk and high risk. The moderate risk technology engine is a homogeneous charge engine operating on avgas and offers a 40% improvement in transportation efficiency over present designs. The high risk technology engine, with a stratified charge combustion system using kerosene-based jet fuel, projects a 65% improvement in transportation efficiency. Technology enablement program plans are proposed herein to set a timetable for the successful integration of each item of required advanced technology into the engine design
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